Last week was bookended by two major news events -- the Boston Marathon bombings on Monday and subsequent capture of suspect Dzhokhar Tsarneav on Friday. As a result, cable news outlets saw a huge spike in ratings all week long, even as much of the social media chatter focused on CNN, which stumbled horrifically through an inaccurate report about a supposed “dark-skinned” suspect.

The error mattered, or seemed to, mostly because CNN, the oldest and most moderate of the cable news networks, is still largely thought of as the go-to television outlet for unbiased coverage of breaking news. The network, a unit of Time Warner Inc. (NYSE:TWX), typically limps along in third place, behind its more polarized rivals, Fox News and MSNBC. Despite those struggles, it has always prided itself on being the most-trusted place to turn when something big happens. During major news events, people flock to CNN for wall-to-wall coverage.

But while that characterization might have been true once upon a time, it’s becoming less and less so. CNN did top its rivals on election night 2012 -- although narrowly, as AdAge reported in November -- but it was edged out by Fox during Hurricane Sandy and the announcement of Pope Francis I.

And last week, as Twitter users both chastised and derided CNN for John King’s faulty Boston bombings report, more viewers once again turned to Rupert Murdoch’s conservative behemoth. Fox News, a unit of News Corp. (NASDAQ:NWSA), pummeled its competition in the ratings as the Boston bombings aftermath and subsequent Tsarneav manhunt unfolded. CNN did see the largest spike in ratings from the prior week -- a jump of 194 percent as Entertainment Weekly reported -- but it wasn’t enough to top the 48 percent ratings jump at Fox.

It gets worse. According to Nielsen’s primetime numbers for the week ending April 21, Fox averaged nearly three million nightly viewers. CNN was significantly behind, with just under two million, while MSNBC trailed both networks with 923,000. Fox’s jump was so substantial, in fact, that it finished first out of every cable network on television -- the first time it’s accomplished that feat since 2005. CNN finished third, behind the usual ratings leader USA Network, a unit of Comcast Corp. (NASDAQ:CMCSA).

Not surprisingly, some conservative media reporters took the time to gloat about the numbers. Breitbart’s John Nolte wrote that the ratings prove, once and for all, that Fox is now “the most trusted name in news,” taking a shot at CNN’s longtime tagline.

“For over a decade, whenever major news broke, Americans were simply expected to abandon their regular news source to tune in to CNN,” Nolte wrote on Friday. “What we've seen lately, though, and without a doubt during the Boston Marathon terror attack, is that this is no longer the case.”

Although Nolte might be jumping the gun with that assessment (a PPP study earlier this year reported that Fox’s trustworthiness hit a record low), credibility erosion is a very real threat for CNN Worldwide, and its new president, Jeff Zucker, who has been making radical programming alternations in an attempt to boost viewership. In the process, he’s been testing the waters to see just how far he can push CNN in the direction of outspoken punditry without alienating a core audience of viewers who still appreciate its middle-of-the-road approach, however rapidly that audience might be vanishing.

The results, at least those we’ve seen come to fruition, have been mixed. Ratings were strong for the debut of Anthony Bourdain’s “Parts Unknown,” but other efforts haven't been so well-received. Earlier this month, CNN’s roundtable discussion program “(Get To) The Point,” a weeklong experiment ostensibly modeled after Fox’s “The Five,” was a colossal failure. The show both flopped in the ratings and took a beating on Twitter.

Should CNN’s credibility suffer in the long term, it would have little to fall back on if Zucker’s changes prove ineffective. As the New York Times’ David Carr pointed out on Sunday, “by marketing itself as the most trusted name in news, CNN is and should be held to a higher standard.”

As it stands, CNN is held to a higher standard, but for how much longer? The answer to that question is tied to the network’s future direction in a very real way. After all, sacrificing credibility for ratings hasn’t exactly hurt Fox News.